awgn_c.txt

AWGN信道的代码

#include <math.h>
#define PI 3.14159
struct    AWGN
{
long      reset;
long      ix;
long      iy;
long      iz;
double     snr;
double     sigma;
double     I_sigma;      //(1/(sigma*sigma))
double     rate;
};
double random_u(struct AWGN *gauss)
{ 
    double temp;
    gauss->ix = (gauss->ix*249) % 61967; 
    gauss->iy = (gauss->iy*251) % 63443;
    gauss->iz = (gauss->iz*252) % 63599;
    temp= ( (double)gauss->ix/(double)61967 + (double)gauss->iy/(double)63443+ (double)gauss->iz/(double)63599 )
    -(int)( (double)gauss->ix/(double)61967+ (double)gauss->iy/(double)63443+(double)gauss->iz/(double)63599 );
    return(temp);     
}
double gauss_g(struct AWGN *gauss)
{
    double u1,u2;
    double x;
    double var;
    var = gauss->sigma;
    u1=random_u(gauss);
    u2=random_u(gauss);
    x=(double)sqrt((double)(-2)*log((double)1-u1))*(double)cos((double)2*(double)PI*u2);
    x=(double)var*x; /*** 常数系数指标准差 ***/
    return(x);
}

void awgn_channel (int input[] , double output[] , struct AWGN *gauss , int len)
{
int i;
double add;
int COLUMN;
COLUMN = len;
for (i=0;i<COLUMN;i++)
{
     add = gauss_g(gauss);
     output = input + add;
}
}